Researchers Identify Gene Linked To Exercise Induced Collapse In Labrador Retrievers

Researchers funded by the AKC Canine Health Foundation at the University of Minnesota College of Veterinary Medicine have identified a gene in Labrador Retriever dogs highly associated with the condition exercise induced collapse (EIC). After intense hunting or retrieving exercise, activities these dogs are trained to perform, affected Labradors start to lose control of their hind limbs.  In most cases, their legs get wobbly and the limbs give out, and in rare cases the dogs may die.  Labradors are the most common dog breed in the world and an estimated two to three percent of Labradors have this condition.

The research team identified a mutant form of the dynamin 1 gene as highly associated with EIC.  The dynamin 1 protein normally functions to maintain proper chemical communication between adjacent nerves, or synaptic transmission.  However, the mutated form of the dynamin protein has appears to have diminished function, interrupting synaptic transmission during intense exercise, and causing the muscle-controlling nerves to not fire when directed to do so.  This is the first natural mutation of this gene identified in any mammal, and its discovery could offer insight into normal as well as abnormal neurobiology in both animals and humans.

Researchers also determined that up to 30 percent of Labrador retrievers are carriers of the mutation, and they developed a genetic test to indicate whether dogs have the normal or mutated forms of the gene.
“The test can not only help confirm the diagnosis, but it can also help dog breeders ensure that no dogs inherit two copies of the mutated gene,” said Edward “Ned” Patterson, D.V.M, Ph.D., professor of veterinary medicine at the University of Minnesota and co-investigator of the study.

Owners can have their dogs tested through their veterinarian by submitting a blood sample to the University of Minnesota Veterinary Diagnostic Laboratory.  To learn how to have your dog tested click here. (http://www.cvm.umn.edu/vdl/ourservices/canineneuromuscular/home.html)

Breeds such as Chesapeake Bay and curly-coated retrievers, which are closely related to Labradors, have also been found to have the dynamin 1 mutation. The research team is now determining what other breeds might be involved and more precisely defining the specific alteration in dynamin function.

The University of Minnesota research team was led by Patterson and James Mickelson, Ph.D, and included Katie Minor, B.A., R.N; Anna  Tchernatynskaia, M.S; and Kari Ekenstedt, D.V.M. Additional members are Susan Taylor, D.V.M., from the Western College of Veterinary Medicine at the University of Saskatchewan, and G. Diane Shelton, D.V.M, Ph.D., from the University of California San Diego School of Medicine.  Shelton and Taylor have investigated EIC for the last thirteen years in an attempt to determine whether the problem was muscular, cardiovascular, or neurological. Suspecting the syndrome had a novel genetic basis, Shelton and Taylor turned to the University of Minnesota researchers in 2001.